Brønsted acid compounds such as hydrofluoric acid and sulfuric acid are highly toxic and corrosive. However, they are useful as catalysts in isomerization, condensation, polymerization, and hydrolysis reactions. For example, hydrofluoric acid is used as a catalyst in conventional industrial processes to perform reactions such as aromatic and olefin alkylation, including in refinery processes for the production of high-octane gasoline, distillate, and lubricating base oil. Efforts to develop safer, alternative acid catalysts have encountered serious challenges.
Lewis acid ionic liquids, such as chloroaluminate, have been investigated for catalysts replacement of hydrofluoric acid and sulfuric acid (see for example, U.S. Pat. No. 5,824,832 to Sherif et al. and Zhu et al., Bulletin of Catalysis Society of India, 2007, 6, 83-89). The effect of the addition of different metals to chloroaluminates was also investigated on the catalytic activity of the resultant complexes. For example, it was reported that the addition of neutral copper (I) chloride (CuCl) into the chloroaluminate ionic liquids increased their catalytic activity (Estager et al., Chemical Society Reviews, 2014, 43, 847-886; Huang et al., Applied Catalysis A: General, 2004, 277, 41-43; Cui et al., Journal of Catalysis, 2014, 320, 26-32; Liu et al., Applied Catalysis A: General, 2008, 346, 189-193).
There is a need for replacing toxic and corrosive acid catalysts that are used in processes such as conventional alkylation reactions. The compositions and methods disclosed herein address these and other needs.